Chaman, Pakistan  People ran from their homes and thick clouds of smoke engulfed the southern Afghan city of Kandahar during overnight strikes by U.S. warplanes, according to a trickle of witnesses arriving in Pakistan on Monday.

One man said he saw at least four people injured in the Sunday night attacks.

"I was standing on my roof when I heard planes overhead, and the next thing I knew there were explosions and panic everywhere," said Nematollah, who like many Afghans uses one name.

"The electricity went out, and people were running in the streets in the darkness," said Nematollah, who arrived early Monday in the border town of Chaman, about 120 kilometers (75 miles) from Kandahar.

Witnesses said Kandahar's airport and the home of Mullah Mohammed Omar, leader of Afghanistan's ruling Taliban militia, appeared to have been the military action's primary targets in the city.

"Many people began to flee the city after the attacks began," said Malang Bacha, who arrived in Chaman with his wife and four children after a three-hour journey in a pickup truck loaded with other fleeing residents.

"It was very hard to see in the dark, but I saw four injured people," Bacha said.

At the border, business appeared to unfold as usual, with no sign of fleeing refugees. Most of the steady stream of people crossing have businesses on the Pakistani side but live in Kandahar.

Noor Mohammed, 20, a male nurse at Kandahar's civilian hospital, said he ran to the roof after hearing explosions. "The airport had been attacked," he said. "You could see the fire from far away."

Mohammed, who said he lives three alleys away from Mullah Mohammed Omar's house, said people started running from the compound shortly afterward. Then, he said, roughly 20 cars came streaming from the gates.

Three missiles hit moments later, he said.

Kandahar's bazaars opened as usual Monday, he said, and aside from some shattered windows there was little evidence of damage.

Mohammed said he went to work briefly this morning and learned that no injured people had been brought in. Chinnaie Hospital, in Kandahar's Chowleen neighborhood, is the city's only civilian hospital, he said.

In Chaman, where Taliban influence and support is strong, people talked of calling a general strike. The strip of dingy, dust-blown road that runs to the border was largely abandoned. In town, about 150 people ranged the streets, tossing stones at shops that were not closed. No windows were broken.

A half-dozen trucks loaded with flour waited for the border to open at 7 a.m. (0200 gmt) to cross into Afghanistan. Pickups filled with blocks of melting ice and bound for Vesh, a market just across the border, also waited for guards to lower the chain that marks the frontier.

Trucks loaded with pomegranates and grapes, many waiting all night for the border to open, lumbered into Chaman, a smugglers' paradise filled with everything from Japanese televisions to blankets and cooking oil smuggled from the Gulf, through Afghanistan and into Pakistan.

Later, demonstrators shouting "Death to America!" marched toward the border, carrying the banner of Jamiat Ulema-e-Islam, the Pakistani political party that most closely echoes Taliban views. The size of the demonstration was not immediately clear.

Fazl Karim, 42, said he was anxious to return home to the Afghan city of Jalalabad. He said he had been in Pakistan hours before the strike looking for a place to move.

"I have all of my family in Jalalabad," Karim said. "I am very worried. I want to get back, but they won't let me."